All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
There is no religious ruling on fictional characters in terms of their belief or disbelief, and you should not think about this or ask about it because it does not lead to doing good deeds and it has no effect on reality.
As for reading such fictional stories, it is permissible if they include a benefit, such as the promotion of moral values and the like, and they are void of Shariah violations such as disbelief or the like of sins.
Allah knows best.